Plating apparatus

ABSTRACT

An objective of the present invention is to provide a plating apparatus capable of improving uniformity of a plating film formed on a substrate. The plating apparatus includes a first potential sensor disposed at a first position in a region between a substrate held by a substrate holder and an anode, a second potential sensor disposed at a second position outside the region between the substrate held by the substrate holder and the anode, and a third potential sensor disposed at a third position different from the second position and outside the region between the substrate held by the substrate holder and the anode. The plating apparatus measures a first potential difference that is a potential difference between the first position and the second position, and a second potential difference that is a potential difference between the second position and the third position and measures a film thickness of the plating film based on a difference between the first potential difference and the second potential difference.

CROSS REFERENCE OF RELATED APPLICATIONS

This application is based upon and claims benefit of priority from Japanese Patent Application No. 2022-077347 filed on May 10, 2022, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present application relates to a plating apparatus.

BACKGROUND ART

As an example of a plating apparatus, a cup type electrolytically plating apparatus is known (see, for example, Patent Literature 1). In the cup type electrolytically plating apparatus, a substrate (for example, a semiconductor wafer) with a surface to be plated being oriented downward is held by a substrate holder, and immersed into a plating solution, and a voltage is applied between the substrate and an anode, thereby precipitating a conductive film on a substrate surface.

In the plating apparatus, generally, a user sets in advance parameters such as a plating current value, a plating time and the like as plating treatment recipes, based on a target plating film thickness and an actual plating area of a substrate to be subjected to a plating treatment, and the plating treatment is performed based on the set treatment recipes (see, for example, Patent Literature 2). Then, a plurality of wafers on the same carrier are subjected to the plating treatment with the same treatment recipe. Also, to measure the plating film thickness after the plating treatment, in general, after the plating treatment of all the wafers in the carrier ends, the carrier containing the wafers is transferred from the plating apparatus to a separate film thickness measuring device, and wafer film thicknesses and wafer in-plane profiles are individually measured.

CITATION LIST Patent Literatures

-   PTL 1: Japanese Patent Laid-Open No. 2008-019496 -   PTL 2: Japanese Patent Laid-Open No. 2002-105695

SUMMARY OF INVENTION Technical Problem

In a plating apparatus, when substrates in the same carrier are subjected to a plating treatment on the same process conditions, variations might be generated in film thickness of a plating film formed on each substrate, due to dimensional tolerance of the substrate, change in state of a plating solution in a plating tank, or the like. Further, when an average film thickness of a plurality of substrates is adjusted, variations might be generated in plating film thickness depending on a location in the same substrate.

In view of above-described situations, one object of the present application is to provide a plating apparatus capable of improving uniformity of a plating film formed on a substrate.

Solution to Problem

According to an embodiment, a plating apparatus is provided, the plating apparatus including a plating tank, a substrate holder that holds a substrate, an anode disposed, in the plating tank, facing the substrate held by the substrate holder, and a film thickness measuring module including a sensor that detects a parameter related to a plating film formed on a surface to be plated of the substrate, the film thickness measuring module measuring a film thickness of the plating film based on a detection value of the sensor during a plating treatment, wherein the sensor includes a first potential sensor disposed at a first position in a region between the substrate held by the substrate holder and the anode, a second potential sensor disposed at a second position outside the region between the substrate held by the substrate holder and the anode, and a third potential sensor disposed at a third position different from the second position and outside the region between the substrate held by the substrate holder and the anode, and the film thickness measuring module measures a first potential difference that is a potential difference between the first position and the second position, and a second potential difference that is a potential difference between the second position and the third position, and measures the film thickness of the plating film based on a difference between the first potential difference and the second potential difference.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view showing an overall configuration of a plating apparatus of a first embodiment;

FIG. 2 is a plan view showing the overall configuration of the plating apparatus of the first embodiment;

FIG. 3 is a longitudinal sectional view schematically showing a configuration of a plating module of the first embodiment;

FIG. 4 is an Iv-Iv view seen from an Iv-Iv direction in FIG. 3 ;

FIG. 5 is a schematic view of a shielding body and a substrate of the first embodiment seen from below;

FIG. 6 is a view showing an example of adjustment of plating conditions by a control module in the first embodiment;

FIG. 7 is a longitudinal sectional view schematically showing a configuration of a plating module according to a modification of the first embodiment;

FIG. 8 is a longitudinal sectional view schematically showing a configuration of a plating module of a second embodiment;

FIG. 9 is a schematic view showing a substrate and a sensor in a plating tank in the present embodiment from a direction perpendicular to a plate surface of a substrate Wf;

FIG. 10 is a schematic view showing a substrate and a sensor in a plating tank in a modification; and

FIG. 11 is a schematic view showing a substrate and a sensor in a plating tank in another modification.

DESCRIPTION OF EMBODIMENTS

Hereinafter, description will be made as to embodiments of the present invention with reference to the drawings. In the drawings illustrated below, the same or corresponding constituent component is denoted with the same reference sign, and redundant description will not be repeated.

First Embodiment

<Overall Configuration of Plating Apparatus>

FIG. 1 is a perspective view showing an overall configuration of a plating apparatus of the first embodiment. FIG. 2 is a plan view showing the overall configuration of the plating apparatus of the first embodiment. The plating apparatus of the present embodiment is for use in subjecting a substrate to a plating treatment. Examples of the substrate include a square substrate and a circular substrate. As shown in FIGS. 1 and 2 , a plating apparatus 1000 includes a loading/unloading module 100, a transfer robot 110, an aligner 120, a prewetting module 200, a presoaking module 300, a plating module 400, a washing module 500, a spin rinse dryer module 600, a transfer device 700, and a control module 800.

The loading/unloading module 100 is a module for loading a substrate such as a semiconductor wafer into the plating apparatus 1000 and unloading the substrate from the plating apparatus 1000, and a cassette for housing the substrate is mounted on the module. In the present embodiment, four loading/unloading modules 100 are arranged in a horizontal direction, but the number and arrangement of the loading/unloading modules 100 are arbitrary. The transfer robot 110 is a robot for transferring the substrate, and configured to deliver the substrate among the loading/unloading module 100, the aligner 120, and the transfer device 700. The transfer robot 110 and the transfer device 700 can deliver the substrate via an unshown temporary stand, when delivering the substrate between the transfer robot 110 and the transfer device 700. The aligner 120 is a module for aligning positions of an orientation flat, a notch and the like of the substrate in a predetermined direction. In the present embodiment, two aligners 120 are arranged in the horizontal direction, but the number and arrangement of the aligners 120 are arbitrary.

The prewetting module 200 is a module for adhering a treatment liquid (prewetting liquid) such as pure water or de-aired water to a surface to be treated of the substrate prior to the plating treatment. In the present embodiment, two prewetting modules 200 are arranged in an up-down direction, but the number and arrangement of the prewetting modules 200 are arbitrary. The presoaking module 300 is a module for etching an oxide film on the surface to be plated of the substrate prior to the plating treatment. In the present embodiment, two presoaking modules 300 are arranged in the up-down direction, but the number and arrangement of the presoaking modules 300 are arbitrary.

The plating module 400 is a module for subjecting the substrate to the plating treatment. In the present embodiment, there are two sets of twelve plating modules 400, each set including three plating modules arranged in the up-down direction and four plating modules arranged in the horizontal direction, and 24 plating modules 400 in total are provided. The number and arrangement of the plating modules 400 are arbitrary.

The washing module 500 is a module for washing the substrate subjected to the plating treatment. In the present embodiment, two washing modules 500 are arranged in the up-down direction, but the number and arrangement of the washing modules 500 are arbitrary. The spin rinse dryer module 600 is a module for rotating the substrate subjected to a washing treatment at a high speed to dry the substrate. In the present embodiment, two spin rinse dryer modules are arranged in the up-down direction, but the number and arrangement of the spin rinse dryer modules are arbitrary.

The transfer device 700 is a device for transferring the substrate among a plurality of modules in the plating apparatus 1000. The control module 800 is a module for controlling the plurality of modules of the plating apparatus 1000, and may include a general computer or a dedicated computer including, for example, an input/output interface between the computer and an operator.

An example of a series of plating treatments by the plating apparatus 1000 will be described. First, the substrate is loaded into the loading/unloading module 100. Subsequently, the transfer robot 110 removes the substrate from the loading/unloading module 100, and transfers the substrate to the aligner 120. The aligner 120 aligns the positions of the orientation flat, notch and the like in the predetermined direction. The transfer robot 110 delivers, to the transfer device 700, the substrate aligned in the direction by the aligner 120.

The transfer device 700 transfers, to the prewetting module 200, the substrate received from the transfer robot 110. The prewetting module 200 subjects the substrate to a prewetting treatment. The transfer device 700 transfers, to the presoaking module 300, the substrate subjected to the prewetting treatment. The presoaking module 300 subjects the substrate to a presoaking treatment. The transfer device 700 transfers, to the plating module 400, the substrate subjected to the presoaking treatment. The plating module 400 subjects the substrate to the plating treatment.

The transfer device 700 transfers, to the washing module 500, the substrate subjected to the plating treatment. The washing module 500 subjects the substrate to the washing treatment. The transfer device 700 transfers the substrate subjected to the washing treatment to the spin rinse dryer module 600. The spin rinse dryer module 600 subjects the substrate to a drying treatment. The transfer device 700 delivers the substrate subjected to the drying treatment to the transfer robot 110. The transfer robot 110 transfers the substrate received from the transfer device 700 to the loading/unloading module 100. Finally, the substrate is unloaded from the loading/unloading module 100.

<Configuration of Plating Module>

Next, a configuration of the plating module 400 will be described. In the present embodiment, 24 plating modules 400 include the same configuration, and hence one plating module 400 will only be described. FIG. 3 is a longitudinal sectional view schematically showing the configuration of the plating module 400 of the first embodiment. As shown in FIG. 3 , the plating module 400 includes a plating tank 410 for containing a plating solution. The plating tank 410 includes a cylindrical inner tank 412 having an open upper surface, and an unshown outer tank provided around the inner tank 412 so that the plating solution overflowing from an upper edge of the inner tank 412 is accumulated.

The plating module 400 includes a substrate holder 440 for holding a substrate Wf with a surface to be plated Wf-a being oriented downward. The substrate holder 440 also includes a power supply contact point to supply power from an unshown power source to the substrate Wf. The plating module 400 includes an elevating/lowering mechanism 442 for elevating and lowering the substrate holder 440. In the embodiment, the plating module 400 includes a rotation mechanism 448 that rotates the substrate holder 440 about a vertical axis. The elevating/lowering mechanism 442 and the rotation mechanism 448 can be achieved by a known mechanism such as a motor.

The plating module 400 includes a membrane 420 that separates an interior of the inner tank 412 in the up-down direction. The interior of the inner tank 412 is divided into a cathode region 422 and an anode region 424 by the membrane 420. The cathode region 422 and the anode region 424 are each filled with the plating solution. In the present embodiment, an example in which the membrane 420 is provided is described, but the membrane 420 does not have to be provided.

In the embodiment, an anode 430 is provided on a bottom surface of the inner tank 412 of the anode region 424. An anode mask 426 for adjusting electrolysis between the anode 430 and the substrate Wf is disposed in the anode region 424. The anode mask 426 is, for example, a substantially plate-shaped member made of a dielectric material and provided on a front surface of (above) the anode 430. The anode mask 426 has an opening through which a current flowing between the anode 430 and the substrate Wf passes. In the present embodiment, the anode mask 426 is formed with a changeable opening dimension, and the opening dimension is adjusted by the control module 800. Here, the opening dimension means a diameter when the opening is circular, and the opening dimension means a length of a side or the longest opening width side when the opening is polygonal. To change the opening dimension in the anode mask 426, a known mechanism can be adopted. In the present embodiment, an example in which the anode mask 426 is provided is described, but the anode mask 426 does not have to be provided. Furthermore, the membrane 420 described above may be provided at the opening in the anode mask 426.

In the cathode region 422, a resistor 450 facing the membrane 420 is disposed. The resistor 450 is a member for uniformly performing the plating treatment in the surface to be plated Wf-a of the substrate Wf. The resistor 450 is a resistor against a current flowing between the anode 430 and the substrate Wf, and made of an electrically insulating material, such as polyvinyl chloride (PVC), in which a plurality of holes are formed as an example. In the present embodiment, the resistor 450 is configured to be movable in the up-down direction in the plating tank 410 by a drive mechanism 452, and a position of the resistor 450 is adjusted by the control module 800. However, the resistor is not limited to this example, and as an example, the resistor 450 may be fixed to the plating tank 410 so that the resistor cannot move in the plating tank 410. The module 400 does not have to include the resistor 450.

Further, in the cathode region 422, a first potential sensor 460 is provided. When the cathode region 422 is provided with the resistor 450, the first potential sensor 460 may be provided between the substrate Wf and the resistor 450. The first potential sensor 460 is supported on a sensor support 468. The first potential sensor 460 may be supported on a side wall of the inner tank 412 or the resistor 450, in place of the sensor support 468. The sensor support 468 may be a paddle for stirring the plating solution. Here, the paddle preferably moves in parallel with a plate surface of the substrate Wf to stir the plating solution but is not limited to this example. In the present embodiment, a plurality of first potential sensors 460 are provided along a radial direction of the substrate Wf. However, the embodiment is not limited to this example, and at least one first potential sensor 460 may only be provided in the plating module 400.

FIG. 4 is an IV-IV view seen from an IV-IV direction in FIG. 3 . As shown in FIGS. 3 and 4 , the first potential sensor 460 is disposed at a first position in a region between the substrate Wf and the anode 430. That is, the first potential sensor 460 is located between the substrate Wf and the anode 430 in a direction perpendicular to the plate surface of the substrate Wf and is disposed at a position overlapping with the substrate Wf as seen from a direction perpendicular to the plate surface of the substrate Wf. The first potential sensor 460 is preferably disposed close to the surface to be plated Wf-a, and as an example, a distance between the first potential sensor 460 and the surface to be plated Wf-a is several hundred micrometers, several millimeters, or tens of millimeters. The first potential sensor 460 detects a potential of a placement location (first position) between the substrate Wf and the anode 430.

Further, a second potential sensor 462 a and a third potential sensor 462 b are provided in the plating tank 410. The second potential sensor 462 a and the third potential sensor 462 b are arranged in a location where there is comparatively no potential change in the plating tank 410. Specifically, the second potential sensor 462 a and the third potential sensor 462 b are arranged at a second position and a third position outside the region between the substrate Wf and the anode 430. That is, as shown in FIG. 4 , the second potential sensor 462 a and the third potential sensor 462 b are arranged at a position that does not overlap with the substrate Wf as seen from the direction perpendicular to the plate surface of the substrate Wf. The second potential sensor 462 a and the third potential sensor 462 b detect a potential of the placement location (second position, third position) away from between the substrate Wf and the anode 430. The second potential sensor 462 a and the third potential sensor 462 b may be provided at positions away from each other. As an example, as shown in FIG. 4 , the second potential sensor 462 a and the third potential sensor 462 b are preferably arranged at different positions as seen from the direction perpendicular to the plate surface of the substrate Wf (that is, in a direction along the plate surface of the substrate Wf). Further, the second potential sensor 462 a and the third potential sensor 462 b may be arranged at different positions in the direction perpendicular to the plate surface of the substrate Wf in place of or in addition to being arranged at different positions along the plate surface of the substrate Wf. Here, the second potential sensor 462 a and the third potential sensor 462 b may be provided in the anode region 424 or in the cathode region 422. Further, when the resistor 450 is provided, the second potential sensor 462 a and the third potential sensor 462 b may be provided between the substrate Wf and the resistor 450 or may be provided between the resistor 450 and the anode 430, in the direction perpendicular to the plate surface of the substrate Wf. Further, the second potential sensor 462 a and the third potential sensor 462 b may be provided in sections different from each other in the anode region 424, between the substrate Wf and the resistor 450 in the cathode region 422, and between the resistor 450 and the anode 430 in the cathode region 422. The second and third potential sensors 462 a and 462 b are supported on sensor supports 469 a and 469 b (see FIG. 4 ). The second and third potential sensors 462 a and 462 b may be supported on the side wall of the inner tank 412, the resistor 450 or the like in place of the sensor supports 469 a and 469 b.

The first potential sensor 460, the second potential sensor 462 a and the third potential sensor 462 b can be made of the same material and/or electrodes with the same shape as an example. At least one of platinum (Pt), gold (Au), carbon (C) and copper (Cu) can be adopted as an electrode material.

Detection signals by the first potential sensor 460, the second potential sensor 462 a and the third potential sensor 462 b are inputted into the control module 800. In the present embodiment, the control module 800 measures a film thickness of a plating film formed on the surface to be plated Wf-a of the substrate Wf based on the detection signals by the first potential sensor 460, the second potential sensor 462 a and the third potential sensor 462 b. Specifically, the control module 800 acquires a first potential difference ΔE12, which is a potential difference between the first position and the second position, and a second potential difference ΔE23, which is a potential difference between the second position and the third position. Then, the control module 800 calculates a modified potential difference ΔE123 (=ΔE12−ΔE23) by subtracting the second potential difference ΔE23 from the first potential difference ΔE12. Specifically, the modified potential difference ΔE123 is calculated by subtracting the potential difference (second potential difference ΔE23) between the second position and the third position where there is comparatively no potential change from the potential difference (first potential difference ΔE12) between the first position near the surface to be plated Wf-a of the substrate Wf and the second position where there is comparatively no potential change in the plating tank 410. When a plurality of first potential sensors 460 are provided, the modified potential difference ΔE123 may be calculated for each of the first potential sensors 460. A change in measured value of the potential in the plating tank 410 is very small and is susceptible to noise. On the other hand, in the present embodiment, an effect of noise is measured by acquiring the potential difference (second potential difference ΔE23) between the second position and the third position where there is comparatively no potential change. Then, the second potential difference ΔE23 is subtracted from the first potential difference ΔE12 to cancel the effect of noise, so that a potential at the first position that changes in response to a change in plating current can be suitably measured. The control module 800 measures the film thickness of the plating film formed on the surface to be plated Wf-a based on the modified potential difference ΔE123 thus calculated.

As a specific example, the control module 800 calculates a plating formation rate on the surface to be plated Wf-a based on the modified potential difference ΔE123. This is based on correlation between the plating current and the potential in the plating treatment. The current plating film thickness can be estimated based on change over time in plating formation rate calculated from start of plating. In the estimation of the plating film thickness based on the modified potential difference ΔE123, a known technique can be adopted. As an example, the control module 800 can estimate a distribution of the plating current in the substrate during the plating treatment based on the modified potential difference ΔE123 and estimate a distribution of the film thickness of the plating film in the substrate based on the estimated distribution of the plating current. In the present embodiment, the first potential sensor 460, the second potential sensor 462 a, the third potential sensor 462 b and the control module 800 correspond to an example of a “film thickness measurement module” for measuring the film thickness of the plating film formed on the surface to be plated Wf-a of the substrate Wf.

<Potential Sensor Abnormality Detection>

Further, the control module 800 (film thickness measuring module) can detect abnormalities in the first, second and third potential sensors 460, 462 a and 462 b based on the first potential difference ΔE12 and the second potential difference ΔE23. As an example, the control module 800 may store in advance an appropriate range of the first potential difference ΔE12 for a plating treatment recipe and determine that an abnormality occurs in the first potential sensor 460 or the second potential sensor 462 a, when the acquired first potential difference ΔE12 is out of the appropriate range for a predetermined determination time. Further, the control module can determine that an abnormality occurs in the second potential sensor 462 a or the third potential sensor 462 b, when the acquired second potential difference ΔE23 is out of a predetermined appropriate range for the predetermined determination time. Therefore, as an example, the control module 800 can determine that the abnormality occurs in the first potential sensor 460, when only the first potential difference ΔE12 is out of the appropriate range for the predetermined determination time. Further, the control module 800 can determine that the abnormality occurs in the second potential sensor 462 a, when both the first potential difference ΔE12 and the second potential difference ΔE23 are out of the appropriate range for the predetermined determination time. Additionally, the control module 800 can determine that the abnormality occurs in the third potential sensor 462 b, when only the second potential difference ΔE23 is out of the appropriate range for the predetermined determination time. However, without being limited to such examples, the control module 800 (film thickness measuring module) may detect abnormalities in the first, second and third potential sensors 460, 462 a and 462 b based on the first potential difference ΔE12 and the second potential difference ΔE23. The control module 800 may notify a user of the abnormality by use of an unshown monitor, buzzer or the like, when the abnormality occurs in any of the first, second and third potential sensors 460, 462 a and 462 b.

<End Point Detection and End Point Prediction>

Further, the control module 800 (film thickness measuring module) may detect an end point of the plating treatment or predict a time to the end point of the plating treatment, based on the modified potential difference ΔE123. As an example, the film thickness measuring module may end the plating treatment, when the film thickness of the plating film reaches a desired thickness, based on the modified potential difference ΔE123. As an example, the film thickness measuring module may calculate a film thickness increase rate of the plating film and predict a time until the desired thickness is reached, that is, the time to the end point of the plating treatment, based on the modified potential difference ΔE123.

<Shielding Body>

Returning to the description of the configuration of the plating module 400, in one embodiment, the cathode region 422 is provided with a shielding body 470 for shielding the current flowing from the anode 430 to the substrate Wf. The shielding body 470 is, for example, a substantially plate-shaped member made of a dielectric material. FIG. 5 is a schematic view of the shielding body 470 and the substrate Wf of the present embodiment seen from below. In FIG. 5 , the substrate holder 440 that holds the substrate Wf is not shown. The shielding body 470 is configured to be movable to a shielding position (shown with a dashed line in FIGS. 3 and 5 ) interposed between the surface to be plated Wf-a of the substrate Wf and the anode 430 and a retreated position (shown with a solid line in FIGS. 3 and 4 ) retreated from between the surface to be plated Wf-a and the anode 430. In other words, the shielding body 470 is configured to be movable to the shielding position below the surface to be plated Wf-a and the retreated position away from below the surface to be plated Wf-a. A position of the shielding body 470 is controlled through the control module 800 by the unshown drive mechanism. The movement of the shielding body 470 can be achieved by a known mechanism such as a motor or solenoid. In examples shown in FIGS. 3 and 5 , the shielding body 470 shields a part of an outer circumferential region of the surface to be plated Wf-a of the substrate Wf in a circumferential direction at the shielding position. In the example shown in FIG. 5 , the shielding body 470 is formed in a tapered shape that becomes thinner toward a center of the substrate Wf. However, without being limited to such examples, the shielding body 470 can be used in any shape predetermined by experiments or the like.

<Plating Treatment>

Next, the plating treatment in the plating module 400 of the present embodiment will be described in more detail. The substrate Wf is immersed into the plating solution of the cathode region 422 by use of the elevating/lowering mechanism 442, and the substrate Wf is exposed to the plating solution. The plating module 400 can subject the surface to be plated Wf-a of the substrate Wf to the plating treatment by applying a voltage between the anode 430 and the substrate Wf in this state. Also, in one embodiment, the plating treatment is performed while rotating the substrate holder 440 by use of the rotation mechanism 448. By the plating treatment, a conductive film (plating film) is precipitated on the surface to be plated Wf-a of the substrate Wf. In the present embodiment, real-time detection by the first, second and third potential sensors 460, 462 a and 462 b is performed during the plating treatment. The control module 800 then measures the film thickness of the plating film based on detection values by the first, second and third potential sensors 460, 462 a and 462 b as described above. Thereby, the change in film thickness of the plating film formed on the surface to be plated Wf-a of the substrate Wf can be measured in real time in the plating treatment.

In the example shown in FIG. 3 , the plating module 400 includes a plurality of first potential sensors 460 for measuring the film thickness of the plating film, and can measure a film thickness of the plating film at a plurality of locations on the surface to be plated Wf-a. Further, when the detection by the first potential sensor 460 is performed with the rotation of the substrate holder 440 (substrate Wf), the detection position by the first potential sensor 460 can be changed, and the film thickness can be measured at a plurality of points in the circumferential direction of the substrate Wf, or in the whole circumferential direction.

Alternatively, the plating module 400 may change a rotation speed of the substrate Wf by the rotation mechanism 448 during the plating treatment. As an example, the plating module 400 may slowly rotate the substrate Wf for the estimation of the plating film thickness by a film thickness estimation module. As another example, the plating module 400 may rotate the substrate Wf at a first rotation speed Rs1 during the plating treatment and may rotate the substrate Wf at a second rotation speed Rs2 slower than the first rotation speed Rs1 while the substrate Wf rotates once or several times every predetermined period (for example, every few seconds). Thus, the plating film thickness of the substrate Wf can be estimated with high accuracy, even when a sampling period by the first potential sensor 460 is small with respect to the rotation speed of the substrate Wf. Here, the second rotation speed Rs2 may be one-tenth of the first rotation speed Rs1.

Thus, according to the plating apparatus 1000 of the present embodiment, it is possible to measure the change in film thickness of the plating film during the plating treatment. Referring to the change in film thickness of the plating film that is thus measured, it is possible to adjust plating conditions including at least one of the plating current value, plating time, position of the resistor 450, opening dimension of the anode mask 426 and position of the shielding body 470 at or after the next plating treatment. The plating conditions may be adjusted by a user of the plating apparatus 1000 or by the control module 800. In the present embodiment, the control module 800 corresponds to an example of a “plating condition adjustment module”. As an example, the adjustment of the plating conditions by the control module 800 may be performed based on a conditional expression or a program predetermined by an experiment or the like.

The adjustment of the plating conditions may be performed when plating another substrate Wf, or the plating conditions in the current plating treatment may be adjusted in real time. As an example, the control module 800 may adjust the position of the shielding body 470. FIG. 6 shows an example of the adjustment of the position of the shielding body 470 during the plating treatment, as an example of the adjustment of the plating conditions by the control module 800. In the example shown in FIG. 6 , a predetermined detection point Sp (see FIG. 5 ) near an outer circumference of the substrate Wf is detected by the first potential sensor 460 with the rotation of the substrate Wf, thereby measuring the change in film thickness in the circumferential direction of the substrate Wf (see an alternate long and short dash line in FIG. 5 ). FIG. 6 shows, in an upper stage, the change in film thickness along a horizontal axis indicating a circumferential position θ and a vertical axis indicating the film thickness th. In the example shown in FIG. 6 , the film thickness th of the plating film formed in a region of θ1 to θ2 is smaller than that in another region. In such a case, the control module 800 may adjust the position of the shielding body 470 with the rotation of the substrate Wf so that the shielding body 470 moves to the retreated position in the region of θ1 to θ2 in which the film thickness th is small (“OFF” in FIG. 6 ), and the shielding body 470 moves to the shielding position in the other region (“ON” in FIG. 6 ). In this way, an amount of plating formed in the region of θ1 to θ2 can be increased to improve uniformity of the plating film formed on the substrate Wf.

Alternatively, the control module 800 may adjust a distance between the substrate Wf and the resistor 450 as real-time adjustment of the plating conditions. According to the research of the present inventors, it is found that the distance between the substrate Wf and the resistor 450 has a comparatively large influence on an amount of plating formed near the outer circumference of the substrate Wf and comparatively does not affect the amount of plating formed in a central region of the substrate Wf. For this reason, as an example, the control module 800 may decrease the distance between the substrate Wf and the resistor 450 when the film thickness of the plating film near the outer circumference is larger than a target and may increase the distance between the substrate Wf and the resistor 450 when the film thickness of the plating film near the outer circumference is smaller than the target. Alternatively, the control module 800 may increase the distance between the substrate Wf and the resistor 450 as the shielding body 470 is at the shielding position longer and may decrease the distance between the substrate Wf and the resistor 450 as the shielding body 470 is at the shielding position shorter. In this way, the uniformity of the plating film formed on the substrate Wf can be improved by adjusting the amount of the plating formed near the outer circumference of the substrate Wf. As an example, the control module 800 may adjust the distance between the substrate Wf and the resistor 450 by driving the elevating/lowering mechanism 442. However, the control module 800 is not limited to this example and may adjust the distance between the substrate Wf and the resistor 450 by moving the resistor 450 with the drive mechanism 452.

Further, the control module 800 may adjust the opening dimension of the anode mask 426 as the real-time adjustment of the plating conditions. As an example, the control module 800 may decrease the opening dimension of the anode mask 426 when the film thickness of the plating film near the outer circumference is larger than a target and may increase the opening dimension of the anode mask 426 when the film thickness of the plating film near the outer circumference is smaller than the target.

<Modification>

FIG. 7 is a longitudinal sectional view schematically showing a configuration of a plating module according to a modification of the first embodiment. Description of a part of a plating module 400 of the modification that overlaps with the plating module 400 of the first embodiment will not be repeated. In the plating module 400 of the modification, a sensor support 468 for supporting a first potential sensor 460 is configured to be movable by a drive mechanism 468 a. Thereby, the first potential sensor 460 supported on the sensor support 468 can be moved, and a detection position by the first potential sensor 460 can be changed. Although not limited, the drive mechanism 468 a may be configured to move the first potential sensor 460 along a radial direction of a substrate Wf. Also, in an example shown in FIG. 7 , a single first potential sensor 460 is mounted on the sensor support 468, but is not limited to this example, and a plurality of first potential sensors 460 may be supported on the sensor support 468 and may be configured to be movable the drive mechanism 468 a.

Second Embodiment

FIG. 8 is a longitudinal sectional view schematically showing a configuration of a plating module 400A of a second embodiment. In the second embodiment, a substrate Wf is held to extend in a vertical direction, that is, with a plate surface being oriented in a horizontal direction. As shown in FIG. 8 , the plating module 400A includes a plating tank 410A that holds a plating solution inside, an anode 430A disposed in the plating tank 410A, and a substrate holder 440A. In the second embodiment, a square substrate will be described as an example of the substrate Wf, but as in the first embodiment, examples of the substrate Wf include the square substrate and a circular substrate.

The anode 430A is disposed facing a plate surface of the substrate Wf in the plating tank. The anode 430A is connected to a positive electrode of a power supply 90, and the substrate Wf is connected to a negative electrode of the power supply 90 via the substrate holder 440A. When a voltage is applied between the anode 430A and the substrate Wf, a current flows through the substrate Wf, and a metal film is formed on the surface of the substrate Wf in the presence of the plating solution.

The plating tank 410A includes an inner tank 412A in which the substrate Wf and the anode 430A are arranged, and an overflow tank 414A adjacent to the inner tank 412A. The plating solution in the inner tank 412A overflows a side wall of the inner tank 412A and flows into the overflow tank 414A.

One end of a plating solution circulation line 58 a is connected to a bottom of the overflow tank 414A, and the other end of the plating solution circulation line 58 a is connected to a bottom of the inner tank 412A. A circulation pump 58 b, a constant temperature unit 58 c and a filter 58 d are attached to the plating solution circulation line 58 a. The plating solution overflows the side wall of the inner tank 412A to flow into the overflow tank 414A and is further returned to the inner tank 412A through the plating solution circulation line 58 a from the overflow tank 414A. Thus, the plating solution circulates between the inner tank 412A and the overflow tank 414A through the plating solution circulation line 58 a.

The plating module 400A further includes a regulation plate 454 that regulates a potential distribution on the substrate Wf, and a paddle 416 that stirs the plating solution in the inner tank 412A. The regulation plate 454 is disposed between the paddle 416 and the anode 430A and includes an opening 454 a for limiting an electric field in the plating solution. The paddle 416 is disposed in the vicinity of the surface of the substrate Wf held by the substrate holder 440A in the inner tank 412A. The paddle 416 is made of, for example, titanium (Ti) or resin. The paddle 416 reciprocally moves in parallel with the surface of the substrate Wf, to stir the plating solution so that sufficient metal ions are uniformly supplied to the surface of the substrate Wf during the plating of the substrate Wf.

The plating module 400A also includes a first potential sensor 460A, a second potential sensor 462Aa and a third potential sensor 462Ab for measuring a plating film thickness of the substrate Wf. FIG. 9 is a schematic view showing the substrate Wf and the first, second and third potential sensors 460, 462Aa and 462Ab in the plating tank according to the present embodiment from a direction perpendicular to the plate surface of the substrate Wf. In examples shown in FIGS. 8 and 9 , the first potential sensor 460A is attached to the paddle 416. Although not limited, in the example shown in FIG. 9 , two paddles 416 are arranged in the vicinity of a surface to be plated of the substrate Wf, and two first potential sensors 460A are attached to each of the two paddles 416. In the examples shown in FIGS. 8 and 9 , the paddle 416 reciprocally moves in parallel with the surface of the substrate Wf, to stir the plating solution and to change a detection position by the first potential sensor 460A. The first potential sensor 460A is not limited to such examples and may be attached to the inner tank 412A or may be supported on an unshown sensor support 468, separate from the paddle 416. As the first, second and third potential sensors 460A, 462Aa and 462Ab, the same sensors as the first, second and third potential sensors 460, 462 a and 462 b of the first embodiment may be adopted. Detection signals by the first, second and third potential sensors 460A, 462Aa and 462Ab are inputted into a control module 800A.

In the plating module 400A in the second embodiment, real-time detection by the first, second and third potential sensors 460A, 462Aa and 462Ab can be performed during a plating treatment in the same manner as in the plating module 400 of the first embodiment. The control module 800A then measures the film thickness of the plating film based on detection values by the first, second and third potential sensors 460A, 462Aa and 462Ab in the same manner as described in the first embodiment. Thereby, change in film thickness of the plating film formed on the surface to be plated of the substrate Wf can be measured in real time in the plating treatment. The control module 800A can also adjust plating conditions based on the film thickness of the plating film in the same manner as described in the first embodiment.

<Modifications>

FIG. 10 is a schematic view showing a substrate Wf and first, second and third potential sensors 460A, 462Aa and 462Ab in a plating tank in a modification. In an example shown in FIG. 10 , four first potential sensors 460A are provided at positions close to four corners, respectively, of a surface to be plated and are configured to be movable inward from the four corners by an unshown drive mechanism. In particular, in a square substrate, a film thickness distribution near a corner of the substrate Wf tends to noticeably affect in-plane uniformity, and therefore the arrangement of the first potential sensors 460A allows measurement of a film thickness at a suitable position on the substrate Wf. In the example shown in FIG. 10 , four first potential sensors 460A are provided, but one to three or five or more first potential sensors 460A may be provided. The first potential sensors 460A may also be configured to move symmetrically in synchronization with one another.

FIG. 11 is a schematic view showing a substrate Wf and first, second and third potential sensors 460A, 462Aa and 462Ab in a plating tank in another modification. In an example shown in FIG. 11 , two first potential sensors 460A are arranged at positions close to long sides, respectively, of a surface to be plated and are configured to be movable along the long sides by an unshown drive mechanism. In particular, in a square substrate, a film thickness distribution near an edge portion of the substrate Wf tends to noticeably affect in-plane uniformity, and therefore the arrangement of the first potential sensors 460A allows measurement of a film thickness at a suitable position on the substrate Wf. In the example shown in FIG. 11 , two first potential sensors 460A are provided, but one or three or more first potential sensors 460A may be provided. The first potential sensors 460A may also be configured to move symmetrically in synchronization with each other.

The present invention can be described in aspects as follows.

[Aspect 1]

According to Aspect 1, a plating apparatus is provided, the plating apparatus including a plating tank, a substrate holder that holds a substrate, an anode disposed, in the plating tank, facing the substrate held by the substrate holder, and a film thickness measuring module including a sensor that detects a parameter related to a plating film formed on a surface to be plated of the substrate, the film thickness measuring module measuring a film thickness of the plating film based on a detection value of the sensor during a plating treatment, wherein the sensor includes a first potential sensor disposed at a first position in a region between the substrate held by the substrate holder and the anode, a second potential sensor disposed at a second position outside the region between the substrate held by the substrate holder and the anode, and a third potential sensor disposed at a third position different from the second position and outside the region between the substrate held by the substrate holder and the anode, and the film thickness measuring module measures a first potential difference that is a potential difference between the first position and the second position, and a second potential difference that is a potential difference between the second position and the third position, and measures the film thickness of the plating film based on a difference between the first potential difference and the second potential difference.

According to Aspect 1, the film thickness of the plating film can be measured during the plating treatment. This can improve uniformity of the plating film formed on the substrate.

[Aspect 2]

According to Aspect 2, in Aspect 1, the film thickness measuring module is configured to estimate a distribution of a plating current in the substrate during the plating treatment based on the difference between the first potential difference and the second potential difference.

[Aspect 3]

According to Aspect 3, in Aspect 2, the film thickness measuring module is configured to estimate a film thickness distribution of the plating film in the substrate based on the estimated distribution of the plating current in the substrate.

[Aspect 4]

According to Aspect 4, in Aspects 1 to 3, the plating apparatus further includes a resistor disposed between the anode and the substrate, and the first potential sensor is disposed between the resistor and the substrate held by the substrate holder.

[Aspect 5]

According to Aspect 5, in Aspects 1 to 4, the plating apparatus further includes a plating condition adjustment module that adjusts plating conditions based on the film thickness of the plating film that is measured by the film thickness measuring module during the plating treatment.

According to Aspect 5, uniformity of the plating film formed on the substrate can be improved.

[Aspect 6]

According to Aspect 6, in Aspect 5, the plating apparatus further includes a shielding body that is movable to a shielding position interposed between the surface to be plated of the substrate and the anode, and a retreated position retreated from between the surface to be plated of the substrate and the anode, and the plating condition adjustment module adjusts a position of the shielding body as the adjustment of the plating conditions.

According to Aspect 6, the uniformity of the plating film formed on the substrate can be improved by using the shielding body.

[Aspect 7]

According to Aspect 7, in Aspect 5 or 6, the plating apparatus further includes a resistor disposed between the anode and the substrate, and a drive mechanism to change a distance between the substrate and the resistor, and the plating condition adjustment module changes the distance between the substrate and the resistor as the adjustment of the plating conditions.

According to Aspect 7, the uniformity of the plating film formed on the substrate can be improved by adjusting the distance between the substrate and the resistor.

[Aspect 8]

According to Aspect 8, in Aspects 5 to 7, the plating apparatus further includes an anode mask disposed above the anode, the anode mask having an opening dimension that is changeable, and the plating condition adjustment module changes the opening dimension of the anode mask as the adjustment of the plating conditions.

According to Aspect 8, the uniformity of the plating film formed on the substrate can be improved by adjusting the opening dimension of the anode mask.

[Aspect 9]

According to Aspect 9, in Aspects 1 to 8, the plating apparatus further includes a rotation mechanism that rotates the substrate holder, and the film thickness measuring module is configured to measure the film thickness of the plating film, with the rotation of the substrate by the rotation mechanism.

According to Aspect 9, a detection position of the substrate by the sensor can be changed by rotating the substrate, and the plating film formed on the substrate during the plating treatment can be more suitably detected.

[Aspect 10]

According to Aspect 10, in Aspects 1 to 9, a plurality of sensors are provided from an outer circumference to an inner circumference of the substrate.

According to Aspect 10, a film thickness of the plating film can be measured at a plurality of positions on the substrate.

[Aspect 11]

According to Aspect 11, in Aspects 1 to 9, a plurality of sensors are provided along an outer edge of the substrate.

According to Aspect 11, the film thickness of the plating film can be measured at the plurality of positions on the substrate.

[Aspect 12]

According to Aspect 12, in Aspects 1 to 9, the film thickness measuring module is configured to move the sensor along a plate surface of the substrate during the plating treatment.

According to Aspect 12, the film thickness of the plating film can be measured at the plurality of positions on the substrate.

[Aspect 13]

According to Aspect 13, in Aspects 1 to 12, the substrate holder is configured to hold the substrate with the surface to be plated being oriented downward in the plating tank.

[Aspect 14]

According to Aspect 14, in Aspects 1 to 12, the substrate holder is configured to hold the substrate with the surface to be plated being oriented to a side in the plating tank.

The embodiments of the present invention have been described above, but the above embodiments of the present invention are described to facilitate understanding of the present invention and are not intended to limit the present invention. Needless to say, the present invention may be changed or modified without departing from the spirit, and the present invention includes equivalents to the invention. Also, in a range in which at least some of the above-described problems can be solved or a range in which at least some of effects are exhibited, any arbitrary combination of the embodiments and the modification is possible, and arbitrary combination or omission of respective constituent components described in claims and description is possible.

All disclosures including the descriptions, claims, drawings and abstracts of Japanese Patent Laid-Open Nos. 2008-19496 (Patent Literature 1) and 2002-105695 (Patent Literature 2) are entirely incorporated herein by reference.

REFERENCE SIGNS LIST

-   -   400 and 400A plating module     -   410 and 410A plating tank     -   416 paddle     -   420 membrane     -   426 anode mask     -   430 and 430A anode     -   440 and 440A substrate holder     -   442 elevating/lowering mechanism     -   448 rotation mechanism     -   450 resistor     -   452 drive mechanism     -   454 regulation plate     -   460 and 460A first potential sensor     -   462 a and 462Aa second potential sensor     -   462 b and 462Ab third potential sensor     -   470 shielding body     -   800 and 800A control module     -   1000 plating apparatus     -   Wf substrate     -   Wf-a surface to be plated 

What is claimed is:
 1. A plating apparatus comprising: a plating tank, a substrate holder that holds a substrate, an anode disposed, in the plating tank, facing the substrate held by the substrate holder, and a film thickness measuring module including a sensor that detects a parameter related to a plating film formed on a surface to be plated of the substrate, the film thickness measuring module measuring a film thickness of the plating film based on a detection value of the sensor during a plating treatment, wherein the sensor comprises: a first potential sensor disposed at a first position in a region between the substrate held by the substrate holder and the anode, a second potential sensor disposed at a second position outside the region between the substrate held by the substrate holder and the anode, and a third potential sensor disposed at a third position different from the second position and outside the region between the substrate held by the substrate holder and the anode, and the film thickness measuring module measures a first potential difference that is a potential difference between the first position and the second position, and a second potential difference that is a potential difference between the second position and the third position and measures the film thickness of the plating film based on a difference between the first potential difference and the second potential difference.
 2. The plating apparatus according to claim 1, wherein the film thickness measuring module is configured to estimate a distribution of a plating current in the substrate during the plating treatment based on the difference between the first potential difference and the second potential difference.
 3. The plating apparatus according to claim 2, wherein the film thickness measuring module is configured to estimate a film thickness distribution of the plating film in the substrate based on the estimated distribution of the plating current in the substrate.
 4. The plating apparatus according to claim 1, further comprising: a resistor disposed between the anode and the substrate, wherein the first potential sensor is disposed between the resistor and the substrate held by the substrate holder.
 5. The plating apparatus according to claim 1, further comprising: a plating condition adjustment module that adjusts plating conditions based on the film thickness of the plating film that is measured by the film thickness measuring module during the plating treatment.
 6. The plating apparatus according to claim 5, further comprising: a shielding body that is movable to a shielding position interposed between the surface to be plated of the substrate and the anode, and a retreated position retreated from between the surface to be plated of the substrate and the anode, wherein the plating condition adjustment module adjusts a position of the shielding body as the adjustment of the plating conditions.
 7. The plating apparatus according to claim 5, comprising: a resistor disposed between the anode and the substrate, and a drive mechanism to change a distance between the substrate and the resistor, wherein the plating condition adjustment module changes the distance between the substrate and the resistor as the adjustment of the plating conditions.
 8. The plating apparatus according to claim 5, further comprising: an anode mask disposed above the anode, the anode mask having an opening dimension that is changeable, wherein the plating condition adjustment module changes the opening dimension of the anode mask as the adjustment of the plating conditions.
 9. The plating apparatus according to claim 1, further comprising: a rotation mechanism that rotates the substrate holder, wherein the film thickness measuring module is configured to measure the film thickness of the plating film, with the rotation of the substrate by the rotation mechanism.
 10. The plating apparatus according to claim 1, wherein a plurality of first potential sensors are provided from an outer circumference to an inner circumference of the substrate.
 11. The plating apparatus according to claim 1, wherein a plurality of first potential sensors are provided along an outer edge of the substrate.
 12. The plating apparatus according to claim 1, wherein the film thickness measuring module is configured to move the first potential sensor along a plate surface of the substrate during the plating treatment.
 13. The plating apparatus according to claim 1, wherein the substrate holder is configured to hold the substrate with the surface to be plated being oriented downward in the plating tank.
 14. The plating apparatus according to claim 1, wherein the substrate holder is configured to hold the substrate with the surface to be plated being oriented to a side in the plating tank. 